A novel approach to determination of amino acids and cyclic heptapeptides using imprinted proteins

For the first time, imprinted proteins (IPs) were used as molecular recognition elements for determination of amino acids (arginine, Arg) and heptapeptides (microcystin-LR, MC-LR) in competitive solid-phase fluorescent assay (CSPA). Bovine serum albumin and ovalbumin were used as protein matrices for imprinting procedures. Preliminary simulation of the interaction of Arg and proteins by molecular docking and dynamic methods was used to predict optimal template concentration during IP synthesis. We developed an original method of increasing the affinity of IP binding sites by imprinting the Arg derivative (Arg-aniline) with greater accessibility of template amino groups. Silica nanoparticles modified with IPs have a high sorption capacity to Arg (7.8 mg g $_{}^{-1}$ ). We have developed procedures for determination of Arg and MC-LR by using CSPA; the linear determination range for Arg is 0.7-10 ng mL $_{}^{-1}$ (LoQ = 0.5 ng mL $_{}^{-1}$ ), while for MC-LR it is 4-60 ng mL $_{}^{-1}$ (LoQ = 2 ng mL $_{}^{-1}$ ). The obtained analytical approach was tested for Arg determination in a biologically active supplement.